1. Field of the Invention
The present invention relates to a treadmill, and more particularly to a treadmill having a treadbelt adjustable to different driving speed according to different loading of the treadbelt.
2. Description of the Prior Art
Various kinds of typical treadmills have been developed and comprise a deck including a treadbelt rotatably attached thereto or engaged therein, and a motor coupled to drive and to rotate the treadbelt relative to the deck. The rotational speed of the treadbelt of some of the typical treadmills may be adjusted to different rate of speed.
For example, U.S. Pat. No. 4,659,074 to Taitel et al. discloses one of the typical treadmills comprising a governor mounted upon one end of a treadmill roller to adjustably limit the rate of speed of the treadbelt. However, a complicated configuration and a number of elements or parts are required to be provided to adjust the treadmill roller and/or the treadbelt to different rotational speed.
U.S. Pat. No. 4,913,396 to Dalebout et al. discloses another typical treadmill comprising a length adjustable gas spring or pneumatic cylinder to adjust the linked support legs and the deck to different elevation and inclination. However, the treadbelt of the treadmill may not be adjusted to different rotational speed.
U.S. Pat. No. 6,758,791 to Kuo discloses a further typical treadmill comprising a tiltable and foldable treadmill device including a motor-driven adjusting device to adjust the linked support legs and the deck to different elevation and inclination. However, similarly, the treadbelt of the treadmill also may not be adjusted to different rotational speed.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional treadmills.